Thread-cutter.



J. A. DOWD.

THREAD CUTTER.

APPLIOATIOI rum) I. 15, ms.

' 1,08 5,026. Patented Jan. 20' 4.

% 6 John A.Dow

8 SHEETS-BK vvvv vv WITNE88E8 mvmron ATTORNEYS J. A. DOW-D.

THREAD CUTTER.

Arrmonlon rum) JA1\.15, 1913.

1,085,026. Patented Jan 20, 1914.

3 8HEETS-BHEET 2.

INVENTOR WIT/(E8858 John A.Dowo( ATTORNEYS COLUIIIA PLANOIIAI N couwummu. D-

J. A. DOWD.

. 5.191s. 1,085,026. Patented Jan. 20, 1914.

a sum snnnr a.

UNITED STATES PATENT OFFICE.

JQHN ALOYSIUS DOWD, FALL RIVER, MASSACHUSETTS.

THREAD-CUTTER.

Specification of Letters Patent.

Patented J an. 20, 1914..

Continuation in part of application Serial No. 714,889, filed August 13, 1912. This application filed January 15,1913. Serial No. 742,212.

To all whom it may concern:

Be it known that I, JOHN A. Down, a

citizen of the United States, and a resident of Fall River, in the county of Bristol and State of Massachusetts, have invented a new and Improved Thread-Cutter, of which the following is a full, clear, and exact description.

This invention relates to improvements in thread cutters, and is adapted to be used with various forms of cutter attachments, as for instance, preferably with the form of attachment disclosed in my co-pending application entitled Thread cutting attachment, filed August 13, 1912, and bearing Serial No. 714,889, of which this case is a continuation in part.

The object in view is to rovide a thread cutter which may be driven at various speeds without affecting the quality of thread produced so a maximum speed may be maintained without injury to the threads being cut.

Another object of the invention is to form a cutter either cylindrical and scalloped so that a straight even thread may be cut, or a thread having beveled ortions may be cut, the beveled portions of course representing what is known as threaded nipples when severed from a tube in which they are out.

A still further object of the invention is the revision of a rotating round or scallope cutter formed with teeth set at an angle whereby the cutter may be set at an angle to the bar being out less than a right angle, such positioning of the cutter causing the cutting teeth to more easily follow the threads and thereby avoid stripping.

A further object of the invention is to provide a cutter having a flat face which may be ground off whenever the cutting teeth are rounded or dulled in order to present a new or sharp engaging portion.

In carrying out the ob ects of the invention, the cutters may be mounted in any suitable attachment for rota-tin the same at any speed and for associating two or more together, if desired. Cutters are made round, or substantially round, and those made substantially round are scalloped in order that when the same are rotated at a certain speed in relation to the tube or bar being cut, a beveled thread will be produced. In ordinary cutters the thread extends arallel with the axis except the usual pitch,

but in the present invention one form of the device is arranged with threads positioned at an angle to the axis so that the axis of the cutter may be set at a less angle than a 1'i ht angle to the bar or tube being cut. In a dit-ion to these advantages, the cutter may be made perfectly flat so that the same may genground off whenever the teeth become A practical embodiment of the invention is represented in the accompanying drawings forming a part of this specification, in which similar characters of reference indicate corresponding parts in all the views.

Figure 1 is a top plan view of a cutter and a fragmentary view of a pipe, the cutter embodymg one form of the lnvention; Fig. 2 is a front view of the structure shown in Fig. 1; Fig. 3 is an edge view of the structure shown in Fig. 1 Fig. 4 is a view similar to Fig. 1 except that the same shows a slightly modified form of the invention; Fig. 5 is a rear view of the structure shown in Fig. 4; Fig. 6 is an ed e view of the structure shown in Fi 4; *ig. 7 is a further slightly modified Term of the invention to that disclosed in Fig. 4; Fig. 8 is a rear elevation of the structure shown in Fig. 7 and Fi 9 is an edge view of the structure shown in Fig. 7

Referrin to the accompanying drawings by numera s, 1 indicates an ordinary tube which is designed to be threaded, and 2 the threading tool or cutter mounted upon a suitable shaft 3 and held in position thereon by any desired means, as for instance key 4. This cutter may be made cylindrical or may be made substantially round and provided with a plurality of scalloped cutting threads or teeth 5 in order to cuta beveled nipple 6 on the pipe or tube 1. It will, of course, be evident that a thread could be cut on a solid bar or other article as well as a pipe. The point on each scallop 5 farthest from the center is designed to cut the deepest thread so that the nipples 6 may be tapered. the taper being regulated by the ratio of s eed between pipe 1 and the cutter 2. If t e cutter is arranged to revolve one thread while the cutter is advanced bodily forward a distance of two threads to one revolution of the tube 1, the bevel of the finished nipple 6 will be twice the distance from the extreme top of each scallop to the extreme bottom of the scallop. If desired each of the scallops 5 could be spaced apart which would result in allowing the cutter to cut any desired taper and have any desired length of unthreaded portion between the opposite ends of a particular nipple. If the cutter 2 was held stationary, that is, against rotation, but fed forward, an ordinary straight thread would be made on the pipe 1. It will be understood that. in orderto vary the taper of the thread on the nipple 6, the cutter 2 and pipe 1 must be-rotated at: certain speeds and the cutter 2 advanced longitudinally of the pipe 1 at a certain speed. \Vhen this ratio is changed there will be a difierence in the thread cut. If it is desired, for instance, to have a long taper, the rotation of the cutter 2 is retarded but the cutter 2 is advanced longitudinally of the tube rapidly, while tube 1 may be rotated rapidly .or at a speed in proportion to the speed of the advancing cutter.

In Figs. 4 to (l is seen a slightly modified form of the invention, in which the cutters 2 are provided with threads or teeth 7, set at an angle to the a'xial line of the cutter, whereby the cutter may be set at an angle to the pipe 1 which is less than a angle. This is intended to cause the cutter to more correctly follow the threads which are cut. and to prevent the striping of the cut threads. The rotation, tie advancing, and the retarding of the cutter is to be accomplished in the same way as in the first structure shown in Figs. 1 to 3. The rotation and the advancement of the cutters, together with the way the same are mounted, is clearly shown in my co-pending application above referred to, but such mounting may be varied or changed as desired, as any suitable mounting which will hold the cutters properly in place and advance the same as desired, Wlll be suiiicient.

In Figs. 7 to 9 will be seen a further slightly modified form of the invention, in which the cuttin face of the cutter '2 is at right. an les to iii ground oft' whenever any of the threads 7' become dull in order to provide a new cutting face. It will be noted from Fig. 9 that this form of cutter does not fit entirely the threads which have been cut, but operates rincipally from the front end of the cutter. n the other forms of the cutter it will be observed that the threads of the cutter fit for their full length against the various threads which have been cut.

From the various forms of the invention above described and shown in the drawings it will be noted that a' thread cutter having scallo ed teeth is utilized in order to. readily prov-i e threaded nipples with any desired taper. It will also be noted that the cutter may have the threads set at an angle so that the cutter itself may be set at a ditlerent e threads 7' and preferably per ectly fiat so that the same may be 1 angle from the usual right angle position of the cutters to a more acute angle while cutting the usual thread. This structure is intended to prevent the usual stripping of threads when the machine is being run comparatively fast. Either the cutter having the threads extending substantially longitudinally thereof or at an angle thereto may be formed with curved cutting teeth for fittin the particular pipe being cut, or may be ormed with straight teeth extending substantially at right angles to the face of the cutter so that the same may be ground off whenever desired for sharpening purposes. In arranging the cutters, one or more may be used, uconvenient number being three when it is desired to cut the ni les with considerable speed. In assemb mg more than one cutter for cutting the same nipple, it is preferable to arrange likecutters in groups so that they will all act substantially in the same way, and thus more easily fol each other.

The expression scalloped threads or scalloped ortions having threads thereon, is inten ed to cover rounded peripheral projections or toothed or pointed projections which have straight sides, or in fact any form of projection which rises from a given point gradually to the apex and then doscends more or less gradually at an opposite angle to a point an equal distance from the center as the first mentioned point.

Having thus described my invention I claim as new and desire to secure by Letters Patent:-

1. In a cutter of the class described, a substantially round body portion having a scalloped threaded periphery.

2. A cutter comprising a substantially disk shaped body having cutting threads arranged on the periphery extending in a general direction parallel with the axis of l the cutter, the threads being inclined sutiil cientlv to give the proper pitch.

8. cutter comprising a substantially round body portion formed of one piece and having a threaded periphery, the threads on said periphery extending substantially arallel with the axis of said cutter, and inclined only sutliciently for giving the desired pitch, all of said threads being curved for fitting a predetermined sized article to be threaded.

4. A cutter formed from a single piece of material comprising a body portion, and banks of cutting teeth arranged on the periphery of the body portion, each of said banks of teeth being substantially Ashaped, so as to cause the cutter to produce a tapering thread.

5. cutter comprising a substantially lindrical body provided with cutting threads on the periphery, said cutting threads being arranged in series and each series being arranged so that the threads thereof will be threads arranged on the peripheral face in arranged progressively at a greater distance from the center and then progressively at a less distance from the center so that as the cutter rotates in operation and is advanced, a tapering thread is reduced, the taper agreeing with the spec of advancement and the rotation of the article being threaded.

6. In a device of the character described, a substantially circular cutter formed of a single piece of material having cutting banks or sections with the abutting points of each section farther from the center of the cutter than the remaining points of said I banks or sections.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

JOHN ALOYSIUS DOWD. lVitnesses:

JOHN T. Monnm'ry, ARTHUR W. DOLTON.

Copies of this patent may be obtained for live cents each, by addressing the Commissioner of Patents, Washington, D. 0. 

